After some research, I discovered that the papaya fruit contains a natural enzyme called papain commonly used as a meat tenderizing agent. This is not a new concept. In regions of South America and Southeast Asia, papaya peels, which have high concentration of papain, have been used as a natural tenderizer to help break down the firm connective tissues in tougher cuts of meat.
In addition to being an effective natural meat tenderizer, papaya is a rich source of vitamins and minerals. Specifically papaya enzymes have been used to treat physical trauma such as sports injuries by helping to alleviate inflammation, which is a good reason for why papaya enzymes are available in a vitamin tablet form.
If you are curious about experimenting with papaya enzymes in your kitchen, you can find them in the vitamin aisle of most grocery stores. Although, take care to avoid over-tenderizing your meats as papain is very efficient at breaking down protein. One tablet in a marinade for an hour or two will do for most cuts.